Modulation of Pituitary LH and Prolactin Pools in Amenorrheic Women II. Effects of Low Dose Estrogen Treatment

Patients with functional amenorrhea, who did not ovulate after 3 treatment courses of clomiphene, underwent repeated LH-RH testing to evaluate the functional pituitary LH pools; pituitary PRL stores were estimated using metoclopramide (MTCL) to stimulate PRL release. Subjects were subdivided into 2 groups according to their LH release patterns to the first LH-RH stimulus, one group consisted of individuals exhibiting a “normal” LH release (group I). The other showed an impaired LH response following LH-RH stimulation (group II). Patients of group I had significantly higher endogenous serum estradiol (E2) levels than those of group II. Administration of small doses of estradiol benzoate (E2-benzoate) for 6 days resulted in preovulatory serum E2 levels in all patients of both groups. As a consequence, a considerable increase of pituitary LH pools was observed as judged from repeated LH-RH stimulation. In group I, patients' serum LH levels were comparable to those seen in normal women at midcycle. The LH release pattern was, however, similar to that occurring during the follicular phase of the menstrual cycle. In patients of group II, LH release to LH-RH was more moderately increased by E2-benzoate treatment than in those of group I. PRL release after MTCL was lower in group II than in group I subjects and was diminished in both groups when compared to the PRL release pattern observed in normally menstruating women. After E2-benzoate application the MTCL stimulated PRL release was augmented being similar to that seen in normal volunteers.